Changing the product key on Windows XP
ZDNet | at | by Mike
If you need to change the product key on either a single or multiple Windows XP machines, here are some pointers. For most Windows XP installs, you'll never need to worry about the validity of the product key assigned to your copy of the OS. However, software does tend to get installed without authorisation, even in the most carefully managed shops, and so from time to time you may need to reset the XP product key. For example, perhaps a user installed a pirated copy of XP but now wants to go legal.